Nondestructive testing is a procedure for determining the quality or characteristics of a structure without permanently altering the structure or the structure's properties. Examples include ultrasonic and radiographic inspection. In the avionics field, nondestructive evaluations of airplane components are done to insure the structural integrity of the airplane. In typical airplane maintenance approaches, a certified inspector performs one or more nondestructive tests on the aircraft. This process may be repeated at regular intervals to monitor the structural health of the aircraft.
While this type of nondestructive testing scheme can be effective, it has several drawbacks. First, the test typically needs to be conducted by trained inspectors, which can incur significant costs, including the potential loss of operational revenue, when having an inspector perform the tests on site. Second, to enable efficient analysis and repetitive comparison over time, a non-subjective decision process driven by inspection data, inspection method parameters, location, decision criteria, and material properties within the context of the structure being inspected may be required. Current inspection approaches may not preserve these necessary components. Although each inspection can be analyzed individually, a collection of inspections may not be analyzed in toto.
To resolve some of the drawbacks of current nondestructive schemes, other structural health management schemes have been developed. In one structural health management technique, ultrasonic transducers can be placed, for example, on the fuselage of the aircraft to be tested. The ultrasonic transducers are then coupled to an onboard testing computer. The testing computer can be used to run nondestructive tests when needed by using the installed ultrasonic transducers.
The above-described system allows for nondestructive testing to be done without having an inspector bring equipment to the aircraft. Additionally, the automated inspection and determination of the state of the inspected material preserves accurate location data, as well as the associated data used to perform the inspection and make the determination. This allows multiple self-referential inspections of an area over an extended period of time, enabling correlation, trending and other sophisticated analysis of the inspection data across vehicles and over time.
Damage assessments can be made by running various damage algorithms using data collected by the sensors. In large structural health monitoring systems, the amount of data to process is very large, requiring processors with high bandwidth capabilities and large amounts of memory, if large blocks of data are processed concurrently. This adds additional costs and complexities to the system, which is undesirable.